CEA Microphone Techniques and Placement

Question 1

What polar pattern captures sound equally from all directions with no directional preference?

Accepted Answer

Omnidirectional

Answer

An omnidirectional polar pattern has equal sensitivity at all angles (360°). Omnidirectional microphones capture the full sonic environment of a space, exhibit no proximity effect, and are often chosen for capturing room ambience and orchestral recordings.

Question 2

For recording an acoustic guitar, what is the generally recommended microphone placement to capture a balanced tone with both warmth and articulation?

Accepted Answer

Pointing at the 12th fret from approximately 6–12 inches away to balance body warmth and string detail

Answer

Placing a microphone at the 12th fret captures a blend between the bass-heavy resonance of the sound hole and the bright, articulate transients from the strings and frets, yielding a naturally balanced acoustic guitar tone. Close placement at the sound hole creates excessive low-frequency buildup.

Question 3

What does the 'hypercardioid' polar pattern offer compared to a standard cardioid?

Accepted Answer

A narrower front acceptance angle with greater side rejection, but a small rear lobe of sensitivity

Answer

Hypercardioid microphones have a narrower front pickup angle (acceptance angle ≈ 105°) providing better isolation from sides compared to cardioid (131°), but they have a small rear lobe of sensitivity (maximum rear rejection at 150° rather than 180°). They are used in live sound for rejection of stage monitors.

Question 4

What is the 'ORTF' stereo microphone technique, and what are its standard specifications?

Accepted Answer

Two cardioid microphones with capsules spaced 17 cm apart and angled 110 degrees apart, simulating the human ears

Answer

ORTF (Office de Radiodiffusion Télévision Française) is a near-coincident stereo technique using two cardioid microphones with capsules spaced 17 cm apart and angled 110 degrees apart, approximating the distance and angle of the human ears to produce a natural, wide stereo image.

Question 5

When recording drums, what technique is used to minimize phase interference between the kick drum close mic and the overheads?

Accepted Answer

Applying the 3:1 rule and checking phase alignment by mono-summing the close mics with the overheads

Answer

Phase issues between the kick close mic and overheads arise from different time-of-arrival to each mic. The 3:1 rule (overhead distance ≥ 3× kick mic distance to the drum) reduces leakage. Phase coherence is verified by checking for low-frequency cancellation when summing tracks to mono.

(CEA) Certified Audio Engineer Practice Test

(CEA) Certified Audio Engineer Practice Test

CEA Microphone Techniques and Placement